Electrical devices, for example, mobile communication devices, are experiencing a constant trend toward miniaturization so that more functions with small dimensions are available. Components which are installed in these devices are consequently also experiencing the trend towards miniaturization.
Reducing the size of components which contain circuit parts of different types is problematic. MEMS parts, for example, filters operating with acoustic waves, comprise functional structures and generally require more or less hermetically sealed cavities in which the functional structures are encapsulated.
It is known to arrange structures of acoustically active filters on a chip and to attach and connect these to a multilayer substrate in a flip-chip arrangement. The multilayer substrate may contain further circuit parts of other types and may be connected to the structures on the chip. A cover over the chip encloses the chip on the multilayer substrate, a cavity optionally being formed between the chip and the substrate.
Another possibility for the encapsulation of MEMS structures consists of TFPs (TFP=Thin-Film Package) with a thin layer of a cover material as the cover.